It is known that in the compact disc production field and other similar fields, discs are packaged in protective cases, generally made of transparent plastic materials and formed of a box-shaped casing of quadrangular configuration. These protective cases are open on one side thereof so that a so-called tray defining a holding housing for the compact disc which can be inserted and retained therein. In addition, a closing element is hinged on one side border of the box-shaped casing.
In a current packaging process, a leaflet generally carrying information related to the music piece or other data recorded on the compact disc is inserted into the holding casing before that casing is inserted into the tray. This leaflet is formed of a quadrangular flat configuration having two opposite side flaps which are bent at an angle of 90.degree. so as to completely cover the corresponding side walls of the holding casing. These leaflet side flaps have been previously bent by an appropriate bending device associated with the disc packaging apparatus. For instance, in European Patent No. 725 006 in the name of the same applicant as herein, a bending device is disclosed which is generally comprised of a transfer head and a counter-mold between which a leaflet to be bent is interposed. When the transfer head is lowered so as to enter the counter-mold, the leaflet side flaps are automatically bent. The leaflets are then picked up from the counter-mold upon the action of the transfer head, and subsequently introduced into the box-shaped casing arranged at a receiving or laying-down station disposed in side-by-side relationship with the bending station.
It has been found, however, that employment of devices of the above type can result in some operating drawbacks, especially when, as often happens, the type of leaflets utilized changes. In particular, the bending operation is greatly affected by the type of paper forming the leaflet and the thickness thereof. In addition, the bending operation is affected by the presence of possible die-cuttings provided on the leaflet in order to facilitate bending of the same at the desired points. Further, even when die-cut leaflets are employed, it has been found that immediately after bending, due to material elasticity, the leaflet flaps have a tendency to again achieve an orientation coplanar with the base portion of the leaflet. Under these circumstances, spontaneous disengagement of the leaflet from the holding casing can result before insertion of the tray is completed.
The above drawbacks have been partially solved by the prior bending device described in U.S. Pat. No. 4,685,277. In the bending station of the device of U.S. Pat. No. 4,685,277, the leaflet is held tightly between a base block and a transfer head which preferably have the same configuration as the base portion of the leaflet. The leaflet is held tight between the base block and the transfer head with its side borders to be bent projecting externally thereof. Two rollers run along two opposite side walls of the base block with the rollers being elastically urged against the base block to thereby cause bending of the side flaps about tapering end portions defining respective perimetric edges of the transfer head. The tapering end portions of the transfer head have an oblique orientation converging away from the base block, so that bending of the flaps, upon the action of the rollers, takes place at an angle greater that 90.degree..
More particularly, the design of the end portions of the transfer head is predetermined so that the bent flaps have a tendency to achieve a 90.degree. orientation relative to the base portion of the leaflet as a result of spring back of the material. With the aid of suction cup-like elements associated with the transfer head, the bent leaflet is then removed from the base block to be inserted into the holding casing of the disc case.
Devices of this type, however, have been found to have certain difficulties when they are to be set up, if employment of leaflets of various different types are utilized. The bending action imposed on the flaps may be appropriate for some types of paper, light papers for example, but unsuitable when heavier papers or papers of different types are utilized. In addition, when some types of paper are employed, bending of the side flaps may be maintained at an angle greater than 90.degree. even after spring back of the material. As a result, disengagement of the leaflet from the transfer head and incorrect introduction of the tray into the box-shaped casing of the disc case are more likely.
It has been also found that the rollers do not always perform a sufficiently neat and precise bending, especially when leaflets of rather heavy paper which have not been die-cut are utilized.